Iain Martin is a political commentator, and a former editor of The Scotsman and former deputy editor of The Sunday Telegraph. He is the author of Making It Happen: Fred Goodwin, RBS and the men who blew up the British economy, published by Simon & Schuster.. As well as this blog, he writes a column for The Sunday Telegraph. You can read more about Iain by visiting his website

As the Scottish referendum looms, a beautiful friendship risks being replaced by bitter enmity

It is the morning after the Scottish referendum in September 2014 and the Scots have voted to leave the Union. With Edinburgh Castle in the background, a grinning Alex Salmond stands triumphant, thumbs aloft, surrounded by delirious Nationalists doing victory jigs while mainlining malt whisky.

Meanwhile, in London, a sombre David Cameron is driven from Number 10 to Buckingham Palace to try to explain to the Queen what has happened to her United Kingdom on his watch. It is not difficult to imagine Her Majesty asking the key question: what happens now?

The answer is that negotiations between the governments in London and Edinburgh would have to get under way immediately. Three hundred years of cross-border ties would have to be unpicked in difficult discussions about the siting of nuclear weapons, the currency, embassies, the national debt and state pensions.

The potential for acrimony is obvious. Yet, in the too often parochial and isolationist climate in which the independence question is debated north of the border, it often seems to be presumed naively by those advocating separation that the talks would be straightforward and friendly.

The possibility that England would quite rightly look ruthlessly to its own interests, or cut up rough, seems not to be considered. Officially, no preparation has been undertaken in Whitehall for the end of the UK. "We don’t go there. We are focused on keeping the Union," says a senior government adviser.

But English MPs are starting to wonder about the implications of the demise of a partnership that stretches back to the 1707 Act of Union. Says one Tory MP in a safe seat: "No-one likes rejection. The morning after an independence vote friendship would turn into an intense economic and political rivalry, with no quarter given by England."

A member of Labour’s shadow cabinet, said any split would bring "great sadness" but agreed attitudes would then change: "The Scots could forget about building our warships. They can’t have their cake and eat it."

Another Tory MP, Adam Holloway says that initially there would be unhappiness in England: "The English would be annoyed at having to have these negotiations, dismayed at the upfront costs then delighted with the consequences. What remains of the UK would then be able to change gear for the 21st century. I’m not sure that many people in my constituency are for Better Together." Better Together is the Scottish campaign fighting to save the Union, under the leadership of Labour’s former Chancellor Alistair Darling.

Despite the polls suggesting that the pro-Union forces have a healthy lead at the moment, the expectation is that the gap will narrow. Independence is still a very real possibility. But already, tensions are rising and cross-border conflict increasingly common. Last week, outrage greeted news that a cancer drug, Axitinib, had been ruled as too costly for NHS patients south of the border, while freely available in Scotland.

The reality is that the two health services have always been separately run and managed since the 1948 creation of the NHS. Since devolution – when the Scottish parliament was given direct control of health policy and budgets – the differences have attracted far more attention.

In higher education the contrast is even more stark. Whereas English students pay tuition fees of £9,000 a year, a university education in Scotland is free, unless the student happens to be from England. Spitefully, fees are charged only for the English, while students from other countries in the European Union qualify for free tuition. There is scope for even more of an argument after independence. Scottish Universities fear an English student invasion, as by European law the Scottish government would no longer be able to charge them fees.

The Scottish government denies that the current financial advantages are the result of Scotland receiving better funding than England. Mr Salmond claims the country is a net contributor to the UK, and that Scotland simply chooses to spend its money according to different priorities. English MPs respond that £1,955 more per person is spent by the Government on services north of the border. This resonates in England, where four out of ten voters believe the Scots do not pay their way, according to a British Social Attitudes survey.

MPs for Scottish seats also get to vote on legislation which affects England – on health, education and so on – while English MPs cannot vote on Scottish affairs. This is the legacy of the lopsided form of devolution which Tony Blair introduced after coming to power in 1997.

In opposition, the Conservatives made noises about introducing English-only voting at Westminster on English affairs, but their coalition partners the Liberal Democrats will not allow it. Recent decisions have caused more tensions. This month, BAE Systems announced it would end warship building in Portsmouth, with the loss of 1,000 jobs. The work will be given to Glasgow instead, where there will also be 800 job losses. BAE claimed it was a purely commercial decision, with no pressure from the Government to look after Scottish jobs first to help the pro-Union campaign. There was great scepticism about the company’s assurances.

Last week’s edition of BBC TVs Question Time, recorded in Portsmouth, was dominated by the subject. Much of the programme was taken up with a discussion on how betrayed the city’s residents feel. A member of the audience asked: "Was Portsmouth sacrificed to keep Scotland in the United Kingdom?" This was greeted with loud applause.

Mr Salmond has long argued that after a "Yes" vote, there would no major problems and only neighbourly goodwill. But it is not hard to envisage negotiations quickly becoming difficult.

The SNP wants nuclear weapons out of Scottish waters, where the UK’s submarines are based. Whitehall would demand that Scotland take its share of the UK’s £1 trillion – and counting – national debt.

There are a myriad of complications that might affect relations between the countries. Would train companies keep running as many trains north of the border, when inter-city trains are often nearly empty north of Carlisle and Newcastle?

Even if the Scots vote to stay in the Union, the aftermath of a "No" vote still looks set to involve increased division and potential conflict. There are demands at Holyrood for the Scottish parliament to have yet more powers, a move which David Cameron has indicated he may support to satisfy Scottish opinion.

George Osborne is an enthusiast believing such a scheme might make the Scottish parliament behave more responsibly. It could mean the devolved parliament taking over control of the tax system and introducing favourable rates for Scotland while retaining the, by international standards, generous UK welfare system. It sounds like a recipe for righteous resentment.

There has long been a healthy rivalry between England and Scotland, but any strains have tended to be resolved in modern times in a spirit of cooperation.

In partnership in the last three centuries the two countries have achieved so much together in the fields of culture, industry, science and, when called upon, war.

The danger now, as the referendum looms, is that a beautiful friendship could be replaced by perpetual outright conflict, whatever the outcome of the referendum.